Archive for September 2009

I was mooching around on Joe Newton's "Thunder in the Night" blog this afternoon and was reading about his header-pic width problem when up popped a comment by a Keith Tilley. I clicked on his name to see his profile and this led to me finding his "Painting on the Edge" blog. If you're into art and the scenery around Caithness and the Scottish Highlands, you should have a good look around his blog - there is some really good stuff there, where you'll find a link to his website, "Scottish Landscape Paintings" .

Keith's blog led me to Jamie Buchanan's "North Light". Jamie is a hotelier and photographer living in the far north of Scotland, and he's put up some very good photos on his blog and on his other place, "Heilan' Light" .

I'd not planned to go out observing, but there was an hour or so of cloudless sky yesterday evening and I had a little time to spare. This was an opportunity to sky-test the Nikon AF-S DX NIKKOR 35mm f/1.8G lens to assess how well it is suited to taking widefield pics of the night sky.

In particular I was looking to see:

how much sky would be captured in the frame;

if a reasonable focus could be achieved using the camera's auto setting;

how quickly the camera sensor would become saturated at f/1.8 and ISO 200;

how much coma would be present at the edges and corners of the image; and

how much star-trailing would be caused when using a static tripod as opposed to using a driven equatorial mount.

The challenges would be to see if I could find a reasonable exposure time, get a small number of images for stacking, and then process-out the vignetting, star-trailing and any light-pollution.

Jupiter was in the southern sky so I pointed the camera at it to get the autofocus set. I then turned off the autofocus and fixed the position of the lens focus ring by the judicious application of duct-tape.

Next, I pointed the camera at the Cassiopeia / M31 Andromeda area and took a few test-frames of various durations. Eventually I settled on an exposure duration of 30 seconds and took 12 pics.

These were stacked in DSS and hurriedly processed in PSCS3, and here's the result:

Mouse-over the pic for details, click it for a bigger pic.

I have to say that I'm quite impressed with the raw images that this lens produced. Shooting with the aperture wide open captured a lot of light, and for a change I had to tone down the details rather than go through the usual routine of having to drag the details out of the murk. I'm damned if I can find any coma in the raw frames, which means that there'll be no need to crop off any bad areas. The expected vignetting was dealt with in PSCS3, the compensation isn't perfect but to be fair I've only done a quick fix, no doubt I could get it better if necessary. The amount of star-trailing was acceptable, and I'm confident that I could get it processed out if necessary and if I had enough time.

And the framing? I'm happy with it for targets the size of Cassiopeia, but the capture-area might be a tad small for meteor-work. Time will tell - between now and the end of the year there will be plenty of opportunities for snapping a few meteor trails (more on that in another post very soon (but don't hold your breath)).

So the CBI says "charge students more", eh? What twaddle is that? FFS, get real. These days most grads start their working life with the hassle of having to pay back a student loan and whatever else they had to borrow to make ends meet. Where are they expected to find the extra dosh? Down the back of the sofa?

There was a time when we had a system where the A-Level, the basic yardstick for measuring the academic ability of a student applying for a place at uni, was something that had to be worked at. It wasn't given away in a box of cornflakes, it was something to be proud of. The peeps at Uni knew that, and set their entrance requirements high so that they could choose from the best of the best. In that way, they could regulate the influx so that their finances were more-or-less balanced, and they weren't taking in more folk than they could afford to educate. Also, the financial strain on the LEAs was less, as the amount of grants/fees that they were paying out was lower, there being less students to fund. Back then, at the end of full-time education the HE achievers got the best jobs, the FE and mid-eds got the good jobs and the less-able got jobs with dirty spanners, mucky wellies or hair-dressing scissors.

For a while now we've had a system where the A-Level format has changed so that it's easy to get good grades, the Unis have dropped their entry requirements to accept the semi-skimmed along with the cream, and grants have been replaced by loans. Then there's the cross-border disparity regarding HE/FE fees. It's an open-door policy by any other name, provided you have the money or can get it somewhere along the line. Gone are days when HE suitability was based on what was in your head, now it depends on what's in your wallet. That's financial discrimination, blowing out of the water the notion that everybody has an equal right to HE, regardless of their background, and based on their true academic ability. Let's remember that it is the Government that wants the country to have more better-educated folk (they want 50% of young people to go to university), so shouldn't the Government be footing the bill, like it used to via the LEA grant/fee system?

Anyway, with the annual HE mass-influx at such a high level, is it any wonder that the educational establishments haven't got enough money to go around? No.

Nowadays at the end of full-time education the job-route is much the same, except that the balance has shifted - because of the higher numbers of folk with "good" A-Levels and HE/FE certs, there are more contenders for the best and good jobs, and hardly any folk to do the mucky spanner work, hence the alleged need to import cheap labour from Eastern Europe while paying for our own versions to draw the dole. Now it's just a thought, but maybe if we sent the migrant workers back home and gave their jobs to our jobless, the savings in dole-money could go into the HE/FE pot. And the jobless total would be lowered, which would look good for the stats-spinners of the Government of the Day.

A conversation during a recent visit to the Uni where I was an undergrad says it all for me. I was looking at the staff-list in the department where I studied, checking to see how many remained of the staff that taught me, when I was engaged in conversation by the current Head of Department. Keen to find out more about the errant alumnus standing before him, he asked when I'd graduated. "1984", I answered. "Ah, back when a degree was worth something, not like today" he replied. I looked in his eyes and I knew that he wasn't joking.

In short, back in the days when I was an undergrad, we had to fight for the right to party. Nowadays, there's an open invitation to every man and his dog, and there's not enough beer to go around. Somebody needs to say "sorry, no more revellers, we're full" and lock the door before we all die of thirst.

I've reprocessed the video data used for the images which I posted on the 13th, using a slightly different method. This has resulted in some subtle improvements without the introduction of some of the processing artefacts that were evident in the previous versions. These are about as good as I can get them:

After spending a good four hours refining the drift-alignment of my pier-mounted scope and then grabbing a load of PEC data using PERecorder, I had a few minutes left to grab some frames of Jupiter before it went out of my field of view.

The purpose of this was to see how the mount was behaving, rather than to do a serious imaging session, but I thought I'd post the results here anyway. Due to the average seeing and the Moon being up it's not my best image of Jupiter, but at least I no longer have to keep faffing with the RumblePad to keep the target centred on the webcam chip.

The two versions of the same pic differ only by the amount of sharpening. I might run them through Noel's Actions later to see if it makes any difference.

Well, I've eventually managed to find time to deal with a few of the holiday snaps. I won't bore you with a load of text - you can have the story in pictures instead. You can expect a few more posts like this over the next few days.

Let's start with 14 pics taken around West Bay - just click the pic below to get the others:

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